Ignition systems to which this invention relates are known, see U.S. Pat. Nos. 4,174,696; 4,063,539; and U.S. Ser. No. 06/221,788, SEEGER, filed Dec. 31, 1980, now U.S. Pat. No. 4,337,744 to which German Disclosure Documents DE-OS No. 2 746 885, DE-OS No. 2 850 113 and DE-OS No. 2 850 115 correspond.
Some of these known ignition systems operate according to the principle of dwell angle decrease and some according to the principle of dwell angle increase. This means that a prescribed basic dwell angle set by a rotating signal generator or an ignition computer is either decreased as a function of speed (a large basic dwell angle is required) or increased (a small basic dwell angle is required). The principle underlying both operations is to determine the count on the counter in dependence on the flow of current on the primary side of the ignition coil, this count in turn influencing the counting process for determining the start of the dwell time. The known closure angle regulators have the common disadvantage that they require a sensed signal, or the output signal of a ignition computer, whose ON/OFF ratio is within a predetermined narrow range. It is therefore necessary to construct different sensor types or computer types depending upon the speed of the particular internal combustion engine.